Filter WordPress posts by multiple taxonomy terms with AJAX and pagination

filter-posts-mt.php

<?php
function vb_filter_posts_mt() {

    if( !isset( $_POST['nonce'] ) || !wp_verify_nonce( $_POST['nonce'], 'bobz' ) )
        die('Permission denied');

    /**
     * Default response
     */
    $response = [
        'status'  => 500,
        'message' => 'Something is wrong, please try again later ...',
        'content' => false,
        'found'   => 0
    ];

    $terms   = $_POST['params']['terms'];
    $page    = intval($_POST['params']['page']);
    $qty     = intval($_POST['params']['qty']);
    $pager   = isset($_POST['pager']) ? $_POST['pager'] : 'pager';
    $tax_qry = [];
    $msg     = '';

    /**
     * Check if term exists
     */
    if (!is_array($terms)) :
        $response = [
            'status'  => 501,
            'message' => 'Term doesn\'t exist',
            'content' => 0
        ];

        die(json_encode($response));
    else :

        foreach ($terms as $tax => $slugs) :
            $tax_qry[] = [
                'taxonomy' => $tax,
                'field'    => 'slug',
                'terms'    => $slugs,
            ];
        endforeach;
    endif;

    /**
     * Setup query
     */
    $args = [
        'paged'          => $page,
        'post_type'      => 'any',
        'post_status'    => 'published',
        'posts_per_page' => $qty,
    ];

    if ($tax_qry) :
        $args['tax_query'] = $tax_qry;
    endif;

    $qry = new WP_Query($args);

    ob_start();
        if ($qry->have_posts()) :
            while ($qry->have_posts()) : $qry->the_post(); ?>

                <article class="loop-item">
                    <header>
                        <h2 class="entry-title"><a href="<?php the_permalink(); ?>"><?php the_title(); ?></a></h2>
                    </header>
                    <div class="entry-summary">
                        <?php the_excerpt(); ?>
                    </div>
                </article>

            <?php endwhile;

            /**
             * Pagination
             */
            if ( $pager == 'pager' )
		vb_ajax_pager($qry,$page);

            foreach ($tax_qry as $tax) :
                $msg .= 'Displaying terms: ';

                foreach ($tax['terms'] as $trm) :
                    $msg .= $trm . ', ';
                endforeach;

                $msg .= ' from taxonomy: ' . $tax['taxonomy'];
                $msg .= '. Found: ' . $qry->found_posts . ' posts';
            endforeach;

            $response = [
                'status'  => 200,
                'found'   => $qry->found_posts,
                'message' => $msg,
                'method'  => $pager,
		'next'    => $page + 1
            ];

            
        else :

            $response = [
                'status'  => 201,
                'message' => 'No posts found',
                'next'    => 0
            ];

        endif;

    $response['content'] = ob_get_clean();

    die(json_encode($response));

}
add_action('wp_ajax_do_filter_posts_mt', 'vb_filter_posts_mt');
add_action('wp_ajax_nopriv_do_filter_posts_mt', 'vb_filter_posts_mt');